Suction device for mica coating machines



1,6 l, June 7 1927' R. SPRENGER ET AL 3 652 SUCTION DEVICE FOR MICA COATING KACHINES Filed Oct. 17. 1925 @9995)@9 @@@QQQQ '@@aaeeeeeeeeee eeeeeecgaeeeee.

wx W J Inventors: Richard Sprenger, Herman Conradt, b9 The'LrAttomeg.

Patented June 7, 1927.

Ftrs srArE s `Ara'lla:1\rr OFFICE. *y

RCHARD.SPRENGERANDJHERMANN-CONRADT, OF HIE)NNIIIGrSIORIE,l GERMANY, AS-

-SIGNORS "IO` GENERAL ELECTRIGCOMPANY, AI. CORBOR AT1ON'OF NEWJ YORKWl SUCTION DEVICE FOR-MICA COATING' MACHINES.

Application filed October 1.7, 1925, Serial No. 63,157, and in Germany January 9, 1925.

trance air limited when the suction orifices are uncovered.

The manufacturing of plates from split l micais carried out by the indlvidualthin Vvis pressedandsecurely held in fronteof an sheets of mica being laid in single layers near each other and overlapped. Onthe I layer there is placed an adhesive substance,y then another layer 1s lai d on and so on yuntil the desired strength of the plate has been obtained. rlChe manufacture of insulating paper stuck with thin sheets of mica is cari-' ried out in the same manner. Hitherto the individuallayers have been laid on by hand g it has7 however, often been tried to form the thin sheets of mica and put them lntov layers mechanically. For this a vacuum was usually used. ln the case of devices workedl by hand7 a hollow suction'head was provided which was connected with an exhauster vor an air pump, and which hadan evenA perforated plate or wire gauze. ln mechanical. arrangement, the suctionplate has, amongst other things, the formof a rotating cylinder. The results obtained with such suction de? vices were not, however,'satisfactoryl `The thin mica sheets are vso oftentelescope'd that the greater number cling together and `asa whole remain stuck tothe suction neo-k even when only',v one or two sheets are caught in trout ofthe suction aperture; In orderjto effect a covering ot the neck only by placingv a sheet in front from time` to time, brushes are arranged which brush away the super-H fluous sheets. ln'h'this case.A however, when the partialvacuum in the neck or the suc? tion aperture was not great enough allthe sheets. were dragged from the apertures.

. ln order to overcome-this drawback .as 4

Through tiese apertures therethen entersy such large quantity'of air that the vacuum in the neck drops to such an extent that the sheets in front of the 'other openings are no` longer held fast enough'.l 1

It. in spite otthis, 'a sufli'ciently high vacuum-had to. be -maintained,l then the' rventilass. tor onthe air pump. had to be. made sorlarge that the necessary expenditures in power made an economical vworking impossible.

aperture by airpressu-re is y It F 'represents the holding force meas:`

ured in grams, A the cross-sectionofwthe.`

aperture infcm.2 and 7) :the Lpartial vacuum 4in the aperture and thesuctionfneclr inem;

waterI pressure,v

HF 1s' to become .as either A or 7) lirnust'be made asvlarge'aspos-I sible.: As represented' above A wasm-ade asv large aspossible.

Further the quant-ity of Qgsignities the 'quantity .in om?y of lai'r suckedl andi Ffa coelicient which m'ustvbeI Xed fory every case,v Aand p'have the same significationl as inVw formula 1.'

Inthe interest -oteiiieient working the fol' lowing `require-Inents are to be fulfilled:r

great. holding `force .(Fzin formula l) and small quantity" 'of airu(Q.y in formula 2);

Inthe case of a Vcustomary suction neck one irequirementY excludes the other.

The second requirement. 7can be fulfilled.: (a) 'by keepingrsxnall the. coefficientF,

(ZJ) keeping small the suction apen-fr ture A,4

(0) by keepinVor small the. under pressure p.

large as possible,V then air when is sucked'through an uncovered aperture is di.-V reetly proportional to the cross-sectionk andl As is known the torce with whieha sheet-'1.l

(a) Thekeeping s1nallof the coefficients F can be obtained ittlieresistancein thesuction "aperture is made large; While.. forY 'eX-r ample3 each suction aperture is connected-by rendering VVthe cleaningv extremely; difficult,

`when the tubes are ychoked by lnfiea'fdust or small thin sheets.

Should the fore F in formula 1, for e2;- ample, be made four times as great, then if the aperture is enlarged according to (b) there results:

A F=A A. p (s) Q=4 A. 1H@ e) or if according to (c) the under pressure p is Q42 A. iin/i5 (e).

If'the equation (4) and (6) are compared it will be seen that it is more advantageous to eiect the increase of the holding force by increasing the partial vacuum than by increasing the cross-section, because the size of the ventilator is dependent on the quantityvof air to be constantly supplied. Now the idea of the Vinvention is that A in the formulas 1 and 3 and 2 and G is made different in size in such a Way that the cross section, in front of which the thin sheets oi mica yare held, is made larger, while the cross-section for theentrance of the air with' uncovered suction aperture is made small.

lt isv now possible to have the partial vacuum and the suction aperture as large as de-l sired, without the air pump having to be eX- tren'ielyv large.

ln the vdrawing` ditl'erent constructional forms according to the idea of the invention are represented. Fig. 1 represents a` form in which the base 1() of the suction neck is providedy with tubes 11 which are widenedat their lower ends 12 in order to obtain a large holding cross-section at their orifices. It will be understood that the upper ends or' the tubes 11 communicate vwith a vacuum. The device may, 'for example, be in the form of a hollow cylinder, the tubes communicating with the interior of the cylinder in which a vacuum is maintained.

Fig.v 2 shows another `form. A metal plate 13 is provided with small openings 14. Y The lower side bears bars or stays 15 which form small boxes providing suction chambers 15a communicating with the vacuum through the openingsr 14.

Fig. 8 shows a similar form to that shown in Fig. 2 in whichpon the bars 15 is arranged a further metal plate 16 provided with apertures 17 in order to create larger bearing surfaces for the mica sheets.

Fig. 4 shows a formiof construction in lwhich the `base of the suction neck is provided withV small stamped cups 18, each of vwhich is connected with the vacuum by one or lmore air suctionl holes 19.

Fig. 5 shows a form of construction similar to Fig. 4, the small cups'20, however,

being formed in a thick plate 2, suction holes 22 being provided to connect the cups with the vacuum.

f In the constructional 'forms according to Figs. 1 to 5 a netting 23 of wire, silkfor string can be arranged in iront ofthe suction oriiices in order to. preventjdust` or small thin sheets from entering the apparatus.

The suction device can naturallybe made in an appropriate form vfor individualcases, for example, often in the case of mica coating machines, the form of a hollow cylinder can be fused to advantage;

What we claim .as new and desire to secure by` Letters Patent of the United States,is:

1. A suction device for mica coating machines and the like, comprising a member` provided with a plurality of apertures varranged to .present a high resistance tothe `entrance of air when uncovered, said aper-v tures being enlarged at their outer ends to give high holding eilect and being mechanicj ally independent of each other so that one or more may be uncovered without opening the uncovered'without uncovering the adjacent openings.

3. A suction devicecomprisingaV hollow r cylinder Yprovided with a plurality of apertures connecting its interior with the outside thereof, said apertures being enlarged at the l exterior of said cylinder to give high holding effect and beingl separated so that one or more may be uncovered without uncovering the adjacent apertures, and means for eX- hausting the air in said cylinder.

4. A suction device for mica coating ina-i chines and the like, comprising a member provided with a plurality otrelatively large suction openings, each opening being connected with a vacuumthrough a relatively sniall aperture whereby the entrancevof air v is restricted when the opening is uncovered, and said openings being separated so that one or more may be uncovered without un covering the adjacent openings, and a screen Varranged over said openings.

In witness whereof, we have hereunto seiL our hands this 23rd day'of September, 1925.

RICHARD sPiiieNoEn.

HERMANN ooNRAnr.` 

